In the Linux kernel, the following vulnerability has been resolved:
ipv4, ipv6: Fix handling of transhdrlen in __ip{,6}_append_data()
Including the transhdrlen in length is a problem when the packet is
partially filled (e.g. something like send(MSG_MORE) happened previously)
when appending to an IPv4 or IPv6 packet as we don't want to repeat the
transport header or account for it twice. This can happen under some
circumstances, such as splicing into an L2TP socket.
The symptom observed is a warning in __ip6_append_data():
WARNING: CPU: 1 PID: 5042 at net/ipv6/ip6_output.c:1800 __ip6_append_data.isra.0+0x1be8/0x47f0 net/ipv6/ip6_output.c:1800
that occurs when MSG_SPLICE_PAGES is used to append more data to an already
partially occupied skbuff. The warning occurs when 'copy' is larger than
the amount of data in the message iterator. This is because the requested
length includes the transport header length when it shouldn't. This can be
triggered by, for example:
sfd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP);
bind(sfd, ...); // ::1
connect(sfd, ...); // ::1 port 7
send(sfd, buffer, 4100, MSG_MORE);
sendfile(sfd, dfd, NULL, 1024);
Fix this by only adding transhdrlen into the length if the write queue is
empty in l2tp_ip6_sendmsg(), analogously to how UDP does things.
l2tp_ip_sendmsg() looks like it won't suffer from this problem as it builds
the UDP packet itself.
Metrics
Affected Vendors & Products
References
History
Mon, 04 Nov 2024 13:15:00 +0000
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-03-02T21:52:32.890Z
Updated: 2024-11-04T14:48:36.111Z
Reserved: 2024-02-20T12:30:33.318Z
Link: CVE-2023-52527
Vulnrichment
Updated: 2024-08-02T23:03:20.760Z
NVD
Status : Awaiting Analysis
Published: 2024-03-02T22:15:48.403
Modified: 2024-03-04T13:58:23.447
Link: CVE-2023-52527
Redhat